Hi,
well regarding comparing LPDDR2 and LPDDR3 you find on wikipedia (
https://en.wikipedia.org/wiki/mobile_ddr#cite_note-lpddr3-5): "The command encoding is identical to LPDDR2, using a 10-bit double data rate CA bus.[SUP][5] (
https://en.wikipedia.org/wiki/mobile_ddr#cite_note-lpddr3-5)[/SUP] However, the standard only specifies 8
n-prefetch DRAM, and does not include the flash memory commands." The page also links to the documents of the both standards. These should clarify your questions.
I think the main issue will be writing a controller for the Cyclone V device. However, I hope this was of any help.
Cheers,
Fade